System and method for aligning vertebrae in the amelioration of aberrant spinal column deviation conditions

ABSTRACT

A system for applying a manipulative force to a target region of a spinal column during a surgical procedure is provided with at least four pedicle screws, at least four elongated levers configured to temporarily engage with the pedicle screws, a linking member configured to link at least two of the elongated levers in a axial direction such that they move in unison, and a cross-linking member configured to link at least two of the elongated levers in a transverse direction such that they move in unison. When the system is assembled, it permits an operator to move the at least four elongated levers in unison to simultaneously rotate the at least four pedicle screws about a spinal column roll axis. Related methods are also provided.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.13/645,589, filed Oct. 5, 2012 which is a continuation of U.S.application Ser. No. 12/857,320, filed Aug. 16, 2010, now U.S. Pat. No.8,361,121, which is a continuation of U.S. application Ser. No.11/202,409, filed Aug. 10, 2005, now U.S. Pat. No. 7,776,072, which is acontinuation-in-part of U.S. application Ser. No. 11/027,026, filed Dec.30, 2004, now U.S. Pat. No. 7,670,358. These applications are hereinincorporated by reference in its entirety.

INCORPORATION BY REFERENCE

All publications and patent applications mentioned in this specificationare incorporated herein by reference in their entirety to the sameextent as if each individual publication or patent application wasspecifically and individually indicated to be incorporated by reference.

FIELD

The present invention relates to methods and apparatus for managementand correction of spinal deformities, such as scoliosis.

BACKGROUND

A serious deficiency presently exists with respect to conventionaltreatment and instrumentation for treating spinal deviation anomalies,such as scoliosis.

This circumstance presents a serious medical challenge, becausescoliosis, other than mild to moderate cases, is a well-recognizedhealth risk.

If scoliosis curvature exceeds 70 degrees, severe twisting of the spineoccurs. This can cause the ribs to press against the lungs, restrictbreathing, and reduce oxygen levels. The distortions may also affect theheart and possibly cause dangerous changes.

Eventually, if the curve reaches more than 100 degrees, both the lungsand the heart can be injured. Patients with this degree of severity aresusceptible to lung infections and pneumonia. Curves greater than 100degrees are associated with elevated mortality rates. A number offactors associated with scoliosis increase the risk for bone loss, whichis referred to as osteopenia. People with osteopenia are at greatlyincreased risk of osteoporosis, a common problem in older women that cancause broken bones and is particularly dangerous for women with ahistory of scoliosis. Experts recommend that children with scoliosis bescreened for osteopenia so that measures can be taken to help preventosteoporosis later.

Present treatment regimens for scoliosis carry their own risks and sideeffects, which include:

Spinal fusion disease. Patients who are surgically treated with fusiontechniques lose flexibility and may experience weakness in back musclesdue to injuries during surgery.

Disk degeneration and low back pain. With disk degeneration, the disksbetween the vertebrae may become weakened and may rupture. Height loss.

Lumbar flatback. This condition is most often the result of a scoliosissurgical procedure called the Harrington technique, used to eliminatelordosis (exaggeration of the inward curve in the lower back). Adultpatients with flatback syndrome tend to stoop forward. They mayexperience fatigue and back pain and even neck pain.

Rotational trunk shift (uneven shoulders and hips).

In some patients, years after the original surgery (particularly withthe first generation of Harrington rods), the weight of theinstrumentation can cause disk and joint degeneration severe enough torequire surgery. Treatment may involve removal of the oldinstrumentation and extension of the fusion into the lower back.

Left untreated, or ineffectively treated, scoliosis carries long-termconsequences.

Pain in adult-onset or untreated childhood scoliosis often developsbecause of posture problems that cause uneven stresses on the back,hips, shoulders, necks, and legs. Studies report, however, that patientswith childhood scoliosis have the same incidence of back pain as thegeneral population, which is very high (60% to 80%). In one studyconducted 20 years after growth had stopped two-thirds of adults who hadlived with curvatures of 20 to 55 degrees reported back pain. In thisstudy, most cases were mild, although other studies have reported thatadults with a history of scoliosis tend to have chronic and more backpain than the general population.

Nearly all individuals with untreated scoliosis at some point developspondylosis, an arthritic condition in the spine. The joints becomeinflamed, the cartilage that cushions the disks may thin, and bone spursmay develop. If the disk degenerates or the curvature progresses to thepoint that the spinal vertebrae begin pressing on the nerves, pain canbe very severe and may require surgery. Even surgically treated patientsare at risk for spondylosis if inflammation occurs in vertebrae aroundthe fusion site.

The consequences of scoliosis are limited to the physical realm. Theemotional impact of scoliosis, particularly on young girls or boysduring their most vulnerable years, should not be underestimated. Adultswho have had scoliosis and its treatments often recall significantsocial isolation and physical pain. Follow-up studies of children withscoliosis who did not have strong family and professional support oftenreport significant behavioral problems.

Older people with a history of scoliosis, even those whose conditionswere corrected, should realize that some negative emotional events inadulthood may possibly have their roots in their early experiences withscoliosis. Many studies have reported that patients who were treated forscoliosis have limited social activities and a poorer body image inadulthood. Some patients with a history of scoliosis have reported aslight negative effect on their sexual life. Pain appears to be only aminor reason for such limitation. An early Scandinavian study reportedthat adults with scoliosis had fewer job opportunities and a lowermarriage rate than the general population.

It is clear, then, that scoliosis treatment options are presentlylacking, and untreated scoliosis (except for mild to lower-moderatecases) is not an acceptable alternative. There are many apparatus whichare designed for attachment to, and positioning adjacent the spinalcolumn, and in many instances, these apparatus are designed for use intreating spinal column anomalies, such as scoliosis. However, all knownsystems are limited by their design and known implementation modes oneither arresting further deleterious rotation of the involved vertebrae,or fixing individual vertebrae once, by some means, they are brought toapproximate a desired orientation and position.

Significant correction of severe scoliotic curvature to the point ofapproximating normal spinal configuration, particularly by a singleprocess, is simply unknown in the art. This is, it is believed, theresult of focus in the field on the positioning substantially seriatimof affected vertebrae. Applying derotational force to a vertebrae inthis manner cannot effect en mass spinal reconfiguration without riskingvertebral fracture at the point of spinal instrumentation fixation,particularly when using conventional instrumentation. Furthermore,significant, focused force applied to any individual vertebra risksspinal cord and related injury. Thus, only force which is inadequate toeffect substantial correction to the entire spinal column is thus farever applied, and correction of scoliotic curvatures are substantiallylimited.

It has become clear to the present inventor that desired levels ofcorrection of spinal column anomalies, such as scoliosis, can only beachieved if the spinal column (or an affected segment thereof) ismanipulated (or “derotated”) substantially as a whole into a desiredconfiguration. To achieve such an objective, force must be appliedsafely to all to-be-derotated vertebrae, and the forces necessary toreconfigure all, or at least a substantial portion of the spinal columnmust be dispersed throughout the affected spinal segments or regions.Nothing in the prior art satisfies these requirements, eitherindividually or in combination.

SUMMARY OF THE DISCLOSURE

In view of the foregoing, it is an object of the present invention toprovide an improved system of spinal instrumentation for use inameliorating aberrant spinal column deviation conditions, such asscoliosis.

It is another object of the present invention to provide an improvedmethod for ameliorating aberrant spinal column deviation conditions,such as scoliosis. It is another object of the present invention toprovide an improved system of spinal instrumentation, and a method forthe use thereof, for ameliorating aberrant spinal column deviationconditions, such as scoliosis, which system and method facilitates theapplication of significant derotational forces to individual vertebra,with substantially reduced risk for fracture thereof upon application ofsuch forces.

It is another object of the present invention to provide an improvedsystem of spinal instrumentation, and associated method for use thereof,in ameliorating aberrant spinal column deviation conditions, such asscoliosis, which system and method facilitates the application of forcesto vertebrae of affected spinal column segments en bloc, therebydistributing otherwise potentially injurious forces in a manner forsafely achieving over-all spinal column correction or derotation.

Applicant's present invention provides a system and method for use ofsuch system which satisfy each of these objectives. Applicant's systemincludes bone screws which are to be implanted in the pedicle region(s)of individual to-be-derotated vertebrae. In the preferred mode of thepresent invention, such bone screws are also to be implanted invertebrae to which balancing forces must be applied as the spinal columnis manipulated en mass to achieve an over-all correction of thecondition. The pedicle implantation provides a stable foundation for theapplication of significant derotational forces, but without undue riskof vertebral fracture.

The system includes a pedicle screw cluster derotation tool. This tool,in the presently preferred embodiment includes shafts or similar pediclescrew engagement members, extending from a common handle or linkedhandle array, which are oriented and configured to extend to and engagethe heads of a number of implanted pedicle screws which will have beenimplanted in adjacent vertebrae to which derotational or balancingforces are to be applied during a spinal column derotation andalignment. The engagement between the pedicle screw cluster derotationtool and the individual pedicle screws is such that, as manipulativeforces are applied to the handle means of pedicle screw clusterderotation tool, forces are transferred and dispersed simultaneouslyamong the engaged vertebrae. Therefore, a practitioner may, in a singlemotion, simultaneously and safely derotate multiple vertebrae of anaffected spinal segment (as well as likewise apply balancing forces toother group(s) of vertebrae which are lateral to the effectedsegment(s).

The effect of practice of the present invention is three-dimensionalcorrection which provides, not only spinal correction to near normalconfiguration, but corrects “rib humps.”

The system of the present invention also includes, in its preferredembodiment, pedicle screws which allow for interfacing with, andfixation relative to pre-contoured spinal rods after a satisfactoryderotation.

The present inventor's approach to the problems described above iscertainly simple, when viewed in hindsight, but it is equally unobvious.In investigative procedures, the presently proposed system and methodhas achieved measure of correction of scoliotic curvature never beforeseen in orthopedic practice.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention may be more easily understood with reference tofigures, which are as follow:

FIG. 1 is a top plan view of an anatomical model of a human spinalcolumn, with components of the system of the present invention shownengaged therewith. The event depicted is that stage of the proposedmethod after which derotational and balancing forces have been appliedto substantially correct a scoliotic curvature.

FIG. 2 is an elevational dorsal view of the anatomical model of a humanspinal column depicted in FIG. 1, but with an unobstructed view ofalready-implanted pedicle screws, and configured as if preceding thederotation step of the proposed method.

FIG. 3 is an elevational side view of the anatomical model of a humanspinal column depicted in FIGS. 1 and 2, with an unobstructed view ofalready-implanted pedicle screws and adjacent, pre-contoured spinal rodswhich will be engaged with the pedicle screws through practice of theproposed method.

FIG. 4 is an example of a pedicle screw which may be used in the systemof the present invention.

FIG. 5 is a depiction of the complimentary forces applied to multiplespinal column segments to achieve an over-all spinal column correction.

FIG. 6 is a three frame x-ray view showing “before and after” views of ascoliosis patient who was treated in an investigational procedure in thedevelopment of the systems and methods of the present disclosure. Thecurvature correction was substantially to normal, and lumbar motion waspreserved notwithstanding.

FIG. 7 is a 4-frame, progressive animation of the stages of correctionof scoliosis according to the embodiments of the present invention.

DETAILED DESCRIPTION

With reference to FIGS. 1-4 and 7, the spinal deviation correctionsystem of the present invention includes a number of pedicle screws 10,each implanted in respective vertebrae to which rotative forces will beapplied in a spinal anomaly correction.

Pedicle screws 10 may be of a variety of designs, such as, for example,are generally depicted in U.S. Pat. No. 6,743,237 (Gray, et al), U.S.Pat. No. 6,827,719 (Ralph, et al), U.S. Pat. No. 6,652,526 (Arafiles),U.S. Pat. No. 6,375,657 (Doubler, et al), the disclosures of which areincorporated herein by reference.

With particular reference to FIG. 4, pedicle screws 10 will include athreaded shank segment 12 and a head segment 14. Head segment will beconfigured with a spinal rod conduit (or channel) 16 or interfacing witha spinal rod 18 (shown in FIG. 3). Spinal rod engagement means 20 serveto fix pedicle screw 10 and spinal rod 18 in relative position andorientation, once a spinal column derotation is complete.

Referring again, generally to FIGS. 1-4, and 7, the system of thepresent invention further includes a pedicle screw cluster derotationtool 30. As depicted in FIG. 1, each pedicle screw cluster derotationtool 30 is configured from a grouping of pedicle screw wrenches 32, by apedicle screw wrench linking member 42 joined together to act in unisonduring use.

Each pedicle screw wrench 32 includes a handle 34, a shaft 36, and adistal end 38 which is configured to reversibly engage the head segment14 of a pedicle screw 10 such that, as shaft 36 is moved while shaftdistal end 38 is engaged with head segment 14, manipulative forces aretransferred to the pedicle screw 10 and, in turn, to the vertebra inwhich such pedicle screw 10 is implanted.

Significant variations of pedicle screw cluster derotation tool 30 arecontemplated by the present invention. For example, the multiplewrenches 32, linked by wrench cross linking members 40, depicted in FIG.1 may be replaced by a single handle member from which extend thefunctional equivalent of the multiple shafts 36 and shaft distal ends 38for simultaneously engaging multiple pedicle screws 10, as depicted.However configured, the object and design of pedicle screw clusterderotation tool 30 is to facilitate simultaneous application ofmanipulative forces to multiple pedicle screws 10 which are implanted ina like number of vertebra. This has the effect of permitting the gross,en bloc application of sufficient derotative forces to affected segmentsof the spinal column in a sufficiently dispersed manner as to avoidinjury to any one vertebra or isolated spinal column segment. This, inturn, facilitates a successful entire-spine, 3D derotation of ascoliosis patient to near normal parameters.

With reference to FIGS. 1-3, 5 and 7 the preferred mode of the presentmethod usually involves application of forces to multiple spinal columnsegments, to achieve an over-all spinal column correction. For example,as depicted in FIGS. 5 and 7 in the case of a single curvature case ofscoliosis, both derotative forces (illustrated by the central forcevector arrow of FIG. 5) to vertebrae involved in scoliotic curvatures,as well as of balancing, or offsetting forces to lateral spinal segments(illustrated by the lateral arrows of FIG. 5) are applied.

The preferred mode of the present method involves pre-contouring spinalrods member 18, as shown in FIG. 3 and frame 2 of FIG. 7. Such acontouring operation involves bending spinal rods member 18 such that,in along two axes (analogous to yaw and pitch in aviation terms), thespinal rods member 18 will substantially define, in one plane, a desiredpost-operative correction of the affected spinal column in reference tosuch two axes.

The spinal rod(s) member 18 are loosely engaged with pedicle screws 10,and in one of the embodiments of the present invention the pre-contouredspinal rod member 18 are rotated from a first orientation, throughapproximately 90 degree to a second orientation, using hex wrenches 50(see frame 3 of FIG. 7), to achieve a substantial correction of thescoliosis in the first two of three axes which will be correctedaccording to one of the embodiments of the present methodology, throughuse of the present system.

The next phase, after 2-D correction as just described, involvesapplying manipulative forces to pedicle screw clusters in reference to athird axis (a “roll axis”, again using aviation terms) using pediclescrew clusters derotation tool(s) 30 (see, inter alia, frame 4 of FIG.7). After this final correction, spinal rod engagement member 20 istightened to fix pedicle screw 10 and spinal rod 18 in relative positionand orientation to secure the corrected spinal column configuration (nowcorrected with reference to all three relevant axes).

Spinal rod engagement member 20 of pedicle screws 10 are tightened,using an anti-torque feature of wrenches 32 (or of their equivalent inan alternative embodiment). This feature, as is well known in the art,allows tightening of nuts and the like, without imparting undue torqueto the underlying apparatus or structure.

As shown in FIG. 6, investigative practice of at least one of thepresent methods disclosed herein achieves efficacy never before seen inthe orthopedic field. The “before picture” is the left hand image ofFIG. 6, and the two remaining images are sagittal and dorsal views ofthe corrected spinal column.

Although the invention has been described with reference to specificembodiments, this description is not meant to be construed in a limitedsense. Various modifications of the disclosed embodiments, as well asalternative embodiments of the inventions will become apparent topersons skilled in the art upon reference to the description of theinvention. It is, therefore, contemplated that the appended claims willcover such modifications that fall within the scope of the invention.

What is claimed is:
 1. A method of applying a manipulative force to atarget region of a spinal column during a surgical procedure, the methodcomprising: implanting a first pedicle screw into a first pedicle of afirst vertebra; implanting a second pedicle screw into a second pedicleof the first vertebra; implanting a third pedicle screw into a firstpedicle of a second vertebra; implanting a fourth pedicle screw into asecond pedicle of the second vertebra; temporarily engaging a firstelongated lever with the first pedicle screw; temporarily engaging asecond elongated lever with the second pedicle screw; temporarilyengaging a third elongated lever with the third pedicle screw;temporarily engaging a fourth elongated lever with the fourth pediclescrew; linking together the first, second, third and fourth elongatedlevers in both a craniocaudal direction and a transverse direction suchthat the first, second, third and fourth elongated levers move togetherin unison; moving the linked together first, second, third and fourthelongated levers in unison to simultaneously rotate the first and thesecond vertebrae through the pedicle screws about a craniocaudal rollaxis; and disengaging the first, second, third and fourth elongatedlevers from their respective pedicle screws before concluding thesurgical procedure.
 2. The method of claim 1, wherein the first, second,third and fourth pedicle screws each comprise a channel configured toreceive a spinal rod.
 3. The method of claim 1, further comprising:installing a spinal rod that extends in a craniocaudal direction betweenat least the first pedicle screw and the third pedicle screw; andbetween the moving and disengaging steps, tightening spinal rodengagement mechanisms on the first and third pedicle screws to securethe spinal rod to the first and third pedicle screws.
 4. The method ofclaim 1, wherein the first vertebra and the second vertebra areimmediately adjacent vertebrae of the spinal column.
 5. The method ofclaim 1, wherein the first, second, third and fourth elongated leverseach extend dorsolaterally, dorsally or dorsomedially away from theirrespective pedicle screws.
 6. The method of claim 1, further comprising:implanting a fifth pedicle screw into a first pedicle of a thirdvertebra; implanting a sixth pedicle screw into a second pedicle of thethird vertebra; temporarily engaging a fifth elongated lever with thefifth pedicle screw; temporarily engaging a sixth elongated lever withthe sixth pedicle screw; linking together the first, second, third,fourth, fifth and sixth elongated levers in both a craniocaudaldirection and a transverse direction such that the first, second, third,fourth, fifth and sixth elongated levers move together in unison; movingthe linked together first, second, third, fourth, fifth and sixthelongated levers in unison to simultaneously rotate the first, secondand third vertebrae through the pedicle screws about a craniocaudal rollaxis; and disengaging the first, second, third, fourth, fifth and sixthelongated levers from their respective pedicle screws before concludingthe surgical procedure.
 7. The method of claim 6, wherein the firstvertebra, the second vertebra and the third vertebra are immediatelyadjacent vertebrae of the spinal column.
 8. The method of claim 1,wherein the moving step comprises applying a manipulative force to asingle handle member located on a construct formed by the linkedtogether first, second, third and fourth elongated levers.
 9. The methodof claim 1, wherein the moving step comprises applying a manipulativeforce to more than one handle located on a construct formed by thelinked together first, second, third and fourth elongated levers.
 10. Asystem for applying a manipulative force to a target region of a spinalcolumn during a surgical procedure, the system comprising: a firstpedicle screw having a proximal portion and a distal portion, the distalportion of the first pedicle screw being configured to be implanted intoa first pedicle of a first vertebra; a second pedicle screw having aproximal portion and a distal portion, the distal portion of the secondpedicle screw being configured to be implanted into a second pedicle ofthe first vertebra; a third pedicle screw having a proximal portion anda distal portion, the distal portion of the third pedicle screw beingconfigured to be implanted into a first pedicle of a second vertebra; afourth pedicle screw having a proximal portion and a distal portion, thedistal portion of the fourth pedicle screw being configured to beimplanted into a second pedicle of the second vertebra; a firstelongated lever having a proximal portion and a distal portion, thedistal portion of the first elongated lever being configured totemporarily engage with the proximal portion of the first pedicle screw;a second elongated lever having a proximal portion and a distal portion,the distal portion of the second elongated lever being configured totemporarily engage with the proximal portion of the second pediclescrew; a third elongated lever having a proximal portion and a distalportion, the distal portion of the third elongated lever beingconfigured to temporarily engage with the proximal portion of the thirdpedicle screw; a fourth elongated lever having a proximal portion and adistal portion, the distal portion of the fourth elongated lever beingconfigured to temporarily engage with the proximal portion of the fourthpedicle screw; a linking member configured to link at least two of theelongated levers in a axial direction such that they move in unison; anda cross-linking member configured to link at least two of the elongatedlevers in a transverse direction such that they move in unison, whereinthe system, when assembled, permits an operator to move the first,second, third and fourth elongated levers in unison to simultaneouslyrotate the first, second, third and fourth pedicle screws about a spinalcolumn roll axis.
 11. The system of claim 10, wherein the first, second,third and fourth pedicle screws each comprise a channel configured toreceive a spinal rod.
 12. The system of claim 10, further comprising: aspinal rod configured to extend in an axial direction between at leastthe first pedicle screw and the third pedicle screw; spinal rodengagement mechanisms provided on the proximal portions of the first andthird pedicle screws configured to secure the spinal rod to the proximalportions of the first and third pedicle screws.
 13. The system of claim10, wherein the first, second, third and fourth elongated levers areeach configured to extend away from their respective pedicle screwsalong a longitudinal axis of the respective pedicle screw.
 14. Thesystem of claim 10, further comprising: a fifth pedicle screw having aproximal portion and a distal portion, the distal portion of the fifthpedicle screw being configured to be implanted into a first pedicle of athird vertebra; a sixth pedicle screw having a proximal portion and adistal portion, the distal portion of the sixth pedicle screw beingconfigured to be implanted into a second pedicle of the third vertebra;a fifth elongated lever having a proximal portion and a distal portion,the distal portion of the fifth elongated lever being configured totemporarily engage with the proximal portion of the fifth pedicle screw;and a sixth elongated lever having a proximal portion and a distalportion, the distal portion of the sixth elongated lever beingconfigured to temporarily engage with the proximal portion of the sixthpedicle screw, wherein the system, when assembled, permits an operatorto move the first, second, third, fourth, fifth and sixth elongatedlevers in unison to simultaneously rotate the first, second, third,fourth, fifth and sixth pedicle screws about a spinal column roll axis.15. The system of claim 10, further comprising multiple handles locatedon a construct formed by the first, second, third and fourth elongatedlevers linked together by the linking member and the cross-linkingmember, such that a manipulative force can be applied to the multiplehandles individually or simultaneously.